In the food processing industry, it is common to prepare many products in sealed containers. Typical products include fruits and vegetables, as well as various condiments which typically are packed in liquid. The products are placed in containers along with any liquid and the containers are sealed. Processing typically is completed by heating the containers to a temperature of 200.degree. F. or so, for the purpose of cooking the ingredients and destroying any bacteria which may be present. In some cases, the containers first are hot filled with product at such an elevated temperature and then, immediately subsequent to filling, are sealed.
Immediately after the sealing and heating of the containers is completed, the containers are cooled to prevent thermophilic spoilage and also to ensure that the end product in the container is as firm or crispy as possible. It has been found that the faster the entire contents of the container can be cooked or heated and then cooled, the better is the quality of the end product when the container subsequently is opened for consumption.
Typically the containers which are used for processed food products are relatively small cans or bottles weighing a total of something less than one pound up to five or six pounds at the most. Consequently, the apparatus which is used to cook and cool such containers needs only to be capable of handling the relatively low weights and small sizes of such containers.
It has been common in the past to place the cans or bottles, after they have been filled and sealed, in a retort which then is closed. A heating medium, such as steam, is directed into the retort under pressure to reach the desired processing temperature. In such apparatus, however, the food product in the container remains stationary, so that a relatively long interval of time is necessary for the transfer of heat from the walls of the container to the center of the food product therein. Similarly, when the product is cooled in the retort by the introduction of cold water or some other cooling medium, a relatively long time is required to ensure that the food in the center of the container reaches the final cooling temperature. It is possible to overcook a portion of the contents of the container, and also it is possible that the center of the container may not be properly cooled, unless relatively long cooling times are employed.
To shorten the cooking and cooling time of foods being processed in sealed containers, various techniques for agitating the contents of the container, while the container is in contact with either a heating or cooling medium, have been developed. One such device is diagrammatically shown and described in the Clifcorn U.S. Pat. No. 2,517,542. The Clifcorn Patent is directed to a heat exchange device for cooking and/or cooling canned food products which are placed in relatively small cans. While the cans are in the heat exchange .medium, they are rotated end-over- end to agitate the product in the can by shifting the head space in the can from one end to the other through each complete revolution of the can. This causes a stirring of the contents to move the food product continuously over the heated or cooled surface of the canto hasten the heat transfer to the center of the can. In addition, this ensures a more uniform heat transfer. This patent does not disclose any actual apparatus for accomplishing the desired purpose, but primarily is directed to a diagrammatic representation of the desired motion.
Another patent which accomplishes a result similar to that which is attained by the action described in the Clifcorn Patent is the Lewinger U.S. Pat. No. 4,301,718. Lewinger also discloses a structure for rotating the food being processed in cans by rotating the cans in a circular path about a central axis while they are in a heating and cooling device. As a consequence, it is possible to shorten the heating and cooling times. An end-over-end tumbling of the contents of the food inside the cans is effected by this apparatus. The manner in which the cans are loaded into the apparatus, and removed from it, is not shown. Essentially, the apparatus is an elongated cylindrical retort with a central rotating cylinder having a number of longitudinal channels in which the cans are placed on their sides about the periphery of the rotating cylinder located within the retort.
Two earlier patents, the Smith U.S. Pat. No. 1,174,189 and the Comer U.S. Pat. No. 1,432,671, also are of interest for a showing of end-over-end heating/cooling devices for canned or bottled products. In the apparatus disclosed in both of these patents, multiple cans or multiple bottles are carried in different sections. The different sections are in the form of baskets or rotating devices which then are rotated about a central axis to periodically invert the cans or bottles during the processing operation.
A Ash U.S. Pat. No. 2,617,635, discloses a device for inverting cartons of bottled beverages to facilitate mixing of the contents. A rotating rack is employed for inverting the beverage containers.
While the foregoing patents are directed to various devices for shortening the heating and cooling times required for processing foods and beverages, none of the patents are suitable for handling foods which are "canned" or packaged in large drums, such as fifty-five gallon drums. There is a need in the food processing industry, however, for a variety of products packaged in such large containers. For example, chilis and similar products are "canned" in fifty-five gallon drums for sale to food processors who then utilize the contents of such drums in further processing. Also, foods packaged in fifty-five gallon drums are utilized by high volume restaurants and the like, since it is much more economical to purchase such foods in fifty-five gallon drum containers than in a large number of smaller containers.
The problems of minimizing the heating and cooling times of foods processed in fifty-five gallon drums are significantly multiplied over those which exist for small containers, simply by virtue of the fact of the large size of the drums and the large amount of food which is contained in the drums, typically over five hundred pounds.
Because fifty-five gallon drums are so large, it has not been possible to employ the simple devices of the type described above to achieve agitation of the contents during the heating and cooling operations.
Accordingly, it is an object of this invention to provide a mechanism for facilitating the heat exchange of the contents in large sealed drums, particularly fifty-five gallon drums or the like, in a food processing operation.